A High Precision Method for Acquiring the Fundamental Component Voltage of IPMSM Under High Modulation Index Conditions

The accuracy of acquiring the fundamental component voltage (FCV) in an interior permanent magnet synchronous motor (IPMSM) is critical for ensuring the precision of torque output in reference current setting algorithms that use IPMSM FCV as an input. This article focuses on developing a high-precision method for acquiring IPMSM FCV under high modulation index conditions (MICs). First, to address the modeling inaccuracies found in traditional inverter nonlinear voltage error (INVE) models under high MICs, the relationship between modulation index, switching device conduction time, and INVE is analyzed. Based on this analysis, the switching state transition points of each switching device at different reference conduction times are categorized into seven distinct cases, leading to the development of an INVE model suitable for high MICs. Second, the influence of INVE and digital control delays on the transmission of IPMSM FCV is thoroughly considered, and a method for accurate IPMSM FCV acquisition under high MICs is proposed. On this basis, torque estimation accuracy in steady-state operation is proposed as the criterion to judge the acquisition accuracy of IPMSM FCV. Finally, the effectiveness and superiority of the proposed method are verified by experiments.